On Tue, Nov 14, 2017 at 6:20 AM, Jakub Jelinek <ja...@redhat.com> wrote:
> On Tue, Nov 14, 2017 at 06:14:10AM -0800, H.J. Lu wrote:
>> Just a thought, should we have a separate patch to add -mprefer-vzeroupper
>> to cover all bases in the future, like
>>
>> /* opt_pass methods: */
>> virtual bool gate (function *)
>> {
>> return TARGET_AVX && (!TARGET_AVX512ER || TARGET_PREFER_VZEROUPPER)
>> && TARGET_VZEROUPPER && flag_expensive_optimizations
>> && !optimize_size;
>> }
>
> If we have it, then shouldn't explicit -mprefer-vzeroupper or
> -mno-prefer-vzeroupper override whatever other optimization
> conditions there are (i.e. everything other than
> TARGET_AVX and TARGET_VZEROUPPER)? I.e. use
> !TARGET_AVX512ER && flag_expensive_optimizations && !optimize_size
> only when the explicit bit is not set for it?
>
I opened:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82990
to track it.
--
H.J.
